The present invention relates to a vehicle-body structure of a vehicle and a manufacturing method of the same.
Vehicles, such as automotive vehicles, are required to increase the rigidity of a vehicle body in order to improve the comfortable ride and the safety. A reinforcing member is provided in a closed-section portion formed by a vehicle-body forming member as a technology to increase the rigidity of the vehicle body. Further, a structure in which an inside of the closed-section portion is partitioned by a partition member is used in the vehicles, such as the automotive vehicles, and Japanese Utility Model Laid-Open publication No. 59-182472 and Japanese Patent Laid-Open publication No. 2009-202620, for example, disclose the technology in which the bulkhead is provided in the closed-section portion of the above-described structure.
The first one of the above-described publications discloses the technology in which, as shown in FIG. 4 of this publication, the inside of the closed-section portion of the side sill formed by the side sill outer and the side sill inner is partitioned by the side sill center, wherein the bulkhead is arranged in a bamboo-joint shape in a space enclosed by the side sill center and the side sill outer. Herein, the bulkhead has flanges at its periphery, and the flanges are joined to the respective inner faces of the side sill center and the side sill outer by both spot welding and adhesive agent.
The second one of the above-described publications discloses the technology in which, as shown in FIGS. 9 and 10 of this publication, the inside of the closed-section portion of the side sill is partitioned by the center pillar inner, wherein the separate bulkheads are arranged in a bamboo-joint shape both in a space enclosed by the center pillar inner and the side sill outer and in another space enclosed by the center pillar inner and the side sill inner.
According to the technologies disclosed in the above-described publications, since the members to which the bulkheads are joined restrain each other, the rigidity of the vehicle-body forming members can be increased. Further, since the sectional shape of the vehicle-body forming members can be easily maintained, vibrations may be restrained form occurring to a certain degree.
However, in the structure having the closed-section portion disclosed in the above-described publications, the bulkhead is arranged only in one of the spaces which are located on both sides of the partition member (the side sill center or the center pillar inner) in the closed-section portion, so that this bulkhead has a function of merely maintaining the sectional shape of this one of the both-side spaces only. Therefore, in order to maintain the sectional shape of the other of the both-side spaces as well, it may be necessary to arrange the bulkhead on the both sides of the partition member in the closed-section portion like the technology disclosed in the second publication described above. This may cause improper increases of parts number or attaching work steps.